1997+ Mercury 35/40HP 2 Cylinder Outboards Service Manual PN 90-826148R2, Page 201Get this manual
4Install bolts and torque to 16.5 lbft(22.4 m) in sequence shown below Thermostat Cover Installation
1Install thermostat components into cylinder blockTorque bolts to 16.5 lbft(22.4 m)ELECTRIC MODELS 1994 THRU 1997 ALL MODELS 1998 AND ABOVE